I suspect one problem is that you wish to have more samples of data displayed in the 6-minute version (360 samples @ 1 per second) than the 1-minute version (60 samples @ 1 per second). Unfortunately, it appears that one cannot programmatically change the History Length from that defined in the front panel. Changing the X-scale multiplier affects the way the X-scale is displayed and not what is actually recorded or plotted in the chart VI. (Incidentally, I notice that your attached VI samples at 300 millisecs intervals too, but I'm sure you knew that). There are ways around this. Try the attached VI. Does this suit? Personally, I prefer the flexibility of graphs (compared to charts) because of this sort of limitation. Richard.